Radiator and oil cooler configuration structure for motorcycles

ABSTRACT

To increase the surface area of an oil cooler and improve the cooling efficiency of an engine for a motorcycle, dual radiators are mounted on the body frame on both right and left sides of a water-cooled engine. Both radiators are inclined relative to a center line of the motorcycle with the larger space between the top ends thereof than the space between the bottom ends thereof on both sides of the engine. Also, the forward portions of the radiators project forwardly from the front end of the engine. An air-cooled oil cooler is provided at the upper space between both radiators in front of the engine and extends laterally across the width of the engine. Furthermore, a cooling system incorporates the radiator and oil cooler configuration.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a radiator and oil cooler configuration structure for motorcycles. More particularly, this invention relates to a radiator and oil cooler configuration structure for motorcycles having radiators mounted on a body frame on both sides of a water-cooled engine.

2. Description of Background Art

In general, motorcycles having radiators on both right and left sides of an engine have been known heretofore as disclosed, for example, in Japanese Patent Laid-open No. Hei 4-292280.

Furthermore, conventional motorcycles typically provide an air-cooled oil cooler under the engine of a motorcycle. This conventional oil cooler suffers from poor cooling efficiency in part because the front wheel blocks air flow over the oil cooler. Furthermore, if the front part of the body frame is covered by a cowling, the lateral extent of the oil cooler in the width direction of the motorcycle is limited because cowlings have a narrow bottom to improve aerodynamics.

One conventional solution is to increase oil cooler surface area by extending the oil cooler in the vertical direction. This solution, however, reduces the cooling efficiency of the engine because the front part of the engine is largely blocked by the oil cooler.

SUMMARY AND OBJECTS OF THE INVENTION

The present invention is intended to resolve the above-noted problems and disadvantages in conventional oil cooler and radiator configurations.

Therefore, it is an object of the present invention to provide a radiator and oil cooler configuration structure for motorcycles which is capable of increasing the surface area of an oil cooler.

It is another object of the invention to increase the surface area of an oil cooler while increasing the cooling efficiency of the engine.

It is yet another object of the invention to provide a cooling system for a motorcycle which efficiently cools the motorcycle.

To achieve the above-mentioned objects, the present invention provides a radiator and oil cooler configuration structure for motorcycles provided with radiators on both sides of a water-cooled engine by mounting the radiators on a body frame such that the radiators are inclined relative to a center line of the motorcycle with a larger inter-radiator space at the top ends thereof than the inter-radiator space at the bottom ends thereof.

To further achieve the objects of the invention, the forward portions of the radiators are provided so as to project out from the front end of the engine.

To still further achieve the objects of the invention, an air-cooled oil cooler is provided at a space in front of the engine and between upper portions of the radiators.

Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus are not limitative of the present invention, and wherein:

FIG. 1 is a side view of a motorcycle incorporating the inventive radiator and oil cooler configuration;

FIG. 2 is a cross-sectional view of a selected portion taken in the direction along cross section line 2--2 of FIG. 1; and

FIG. 3 is a diagram of a liquid coolant circulation system for the radiators.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, a preferred embodiment of the present invention will be described with reference to the drawings.

In FIG. 1, the body frame 5 of the motorcycle includes a pair of main frames 6 extending in an upward and forward direction. The pair of main frames 6 widen as they extend upward by curving outwardly in right and left side directions of the motorcycle. The body frame 5 further includes a pair of auxiliary frames 7, under the main frames 6, extending upward and forward and which widen as they extend upward by curving outwardly in right and left directions.

A head pipe 8 commonly connects the front ends of both main frames 6 and both auxiliary frames 7. Furthermore, a pair of right and left connecting frames 9 connect the rear ends of the main frames 6 and auxiliary frame 7. A seat rail 10 extends backward and is connected to both connecting frames 9 at the front end thereof.

A front fork 12 is supported by the head pipe 8 which permits steering of the motorcycle in cooperation with the steering handle 11. A front wheel W_(F) is supported at the bottom ends of the front fork 12. A fuel tank 13 is mounted on both main frames 6. Also, a seat 14 is fixed on the seat rail 10, and the front part of the body frame 5 is covered with a cowling 15.

A power unit P including an engine E and speed change gearing mechanism M connected to the engine E is mounted on the main frames 6 and auxiliary frames 7.

The rear wheel W_(R) is supported at the rear ends of a rear fork 17 which, in turn, is swingably supported at the front end thereof by a bracket 16. Bracket 16 is provided on the speed change gearing mechanism M, and a cushion 18 is provided between the fork 17 and connecting frame 9. Power from the speed change gearing mechanism M is transmitted to the rear wheel W_(R) through a endless chain 19.

Preferably, the engine E is a two cylinder water-cooled V-engine including a front engine bank 20_(F) having one cylinder and cylinder head in combination and a rear engine bank 20_(R) including the other cylinder and cylinder head. In combination, the front and rear engine banks 20_(F) and 20_(R) are provided in a substantially V-shaped configuration. The upper portion of the front engine bank 20_(F) is provided between both auxiliary frames 7 and the upper portion of the rear engine bank 20_(R) is provided between both connecting frames 9. Furthermore, front and rear engine banks 20_(F) and 20_(R) are supported by the main frames 6 and the auxiliary frames 7.

Referring now to FIG. 2, both engine banks 20_(F) and 20_(R) have a cam chain chamber 22 on one side of the combustion chamber 21. The cam chain chamber 22 is provided on the left side (right side in FIG. 2) of the combustion chamber 21 from the perspective of a motorcycle driver and is supported by the main frames 6 and auxiliary frames 7.

The distance L_(R) from the right end (left end in FIG. 2) of both engine banks 20_(F) and 20_(R) to the body center line C is smaller than the distance L_(L) from the left end (right end in FIG. 2) of both engine banks 20_(F) and 20_(R) to the body center line C. In other words, both engine banks 20_(F) and 20_(R) are offset to the left relative to the body center line C.

Radiators 23_(L) and 23_(R), which may be constructed in a form of, eg. a flat rectangle, are provided on both sides of the front engine bank 20_(F) of the engine E. Also, the forward portions of the radiators (23_(L) and 23_(R)) project outward from the front end of the front engine bank 20_(F) as shown by the dotted lines in FIG. 1.

The radiators 23_(L) and 23_(R) are preferably inclined relative to the body center line C with a larger space between both radiators 23_(L) and 23_(R) at the top ends thereof than the space at the bottom ends thereof.

In other words, the radiators 23_(L) and 23_(R) are mounted on the auxiliary body frame 7 such that the radiators 23_(L) and 23_(R) are inclined relative to a center line C of the motorcycle with a larger inter-radiator space at the top ends thereof than the inter-radiator space at the bottom ends thereof. Furthermore, the radiators 23_(L) and 23_(R) are symmetrically mounted with respect to the body center line C.

Thus, the upper portions of these both radiators 23_(L) and 23_(R) are fixedly supported by both auxiliary frames 7 and 7, and the lower portions of these radiators 23_(L) and 23_(R) are fixedly supported by a support plate 25 which, in turn, is fixed to the bottom of the front engine bank 20_(F).

Because the front engine bank 20_(F) of the engine E is offset to the left side relative to the body center line C and both radiators 23_(L) and 23_(R) are symmetrically mounted relative to the body center line C on both sides of the front engine bank 20_(F), the space between the right radiator 23_(R) and the front engine bank 20_(F) is larger than the space between the left radiator 23_(L) and the front engine bank 20_(R). This invention utilizes this relatively larger space between the right radiator 23_(R) and the front engine bank 20_(F) by inserting a cooling fan 24 between the front engine bank 20_(F) of the engine E and the right radiator 23_(R).

The cooling fan 24 blasts cooling air from the front engine bank 20_(F) side to the right radiator 23_(R) side and is fixedly supported to the inboard side of the right radiator 23_(R). As further shown in FIGS. 1 and 2, the cooling fan 24 also forces air to flow laterally across the front engine bank 20_(F) and the oil cooler 30.

By providing the cooling fan 24 between the right radiator 23_(R) and the front engine bank 20_(F), the cooling fan 24 is effectively hidden from view. In this way, the overall appearance of the motorcycle is not degraded by the cooling fan 24.

As further shown in FIG. 2, an air-cooled oil cooler 30 is provided between upper portions of both radiators 23_(L) and 23_(R) in front of the front engine bank 20_(F) of the engine E. The oil cooler 30 has a shape extending in the width (lateral) direction of the motorcycle in order to increase the surface area and, thereby, cooling efficiency.

To further increase the surface area and cooling efficiency, the oil cooler 30 is provided at the upper space that is provided between both radiators 23_(L) and 23_(R). In other words, the oil cooler 30 takes advantage of the relatively larger space that is provided between the upper portions of the radiators 23_(L) and 23_(R) by inclining the radiators relative to the center line C.

A support member 32 is provided between both auxiliary frames 7 of the body frame 5 above the oil cooler 30. A fixture 31 mounted at the top of the oil cooler 30 is fixedly supported by the supporting member 32.

The radiators 23_(L) and 23_(R), oil cooler 30, and cooling fan 24 are components of the cooling system for the motorcycle.

As shown in the coolant diagram of FIG. 3, both radiators 23_(L) and 23_(R) are connected to the engine E in parallel. Liquid coolant derived from both engine banks 20_(F) and 20_(R) of the engine E is guided to the rear of the right radiator 23_(R) through the common guide tube 26. The rear of the right radiator 23_(R) and the front of the left radiator 23_(L) are connected through a first guide tube 27₁. A portion of liquid coolant introduced in the rear of the right radiator 23_(R) is guided to the front of the left radiator 23_(L) through the first guide tube 27₁ without flowing in the right radiator 23_(R).

On the other hand, the residual portion of the liquid coolant introduced in the rear of the radiator 23_(R) flows into the right radiator 23_(R) and reaches the front of the radiator 23_(R), and is then guided to the rear of the left radiator 23_(L) through a second guide tube 27₂ connected between the front of the right radiator 23_(R) and the rear of the left radiator 23_(L).

The liquid coolant introduced from the guide tube 27₁ to the front of the left radiator 23_(L) flows in the radiator 23_(L) and reaches the rear of the left radiator 23_(L), and then returns to the engine E through the return guide tube 28 with the aid of a circulation pump 29 together with the liquid coolant which has been guided through the second guide tube 27₂.

Next, the operation of the preferred embodiment is described. The cooling fan 24, located between the radiator 23_(R) on the right side of the front engine bank 20_(F) of the water-cooled engine E and the engine bank 20_(F), blasts cooling air from the front engine bank 20_(F) side to the radiator 23_(R) side. The cooling fan 24 also forces air to flow across the front engine bank 20_(F) and the oil cooler 30 thereby improving the cooling efficiency of those elements.

Although the cooling fan 24 is shielded from the outside by the radiator 23_(R), it can still effectively cool at least the radiator 23_(R), front engine bank 20_(F) and oil cooler 30. Accordingly, the radiator 23_(R) is efficiently cooled without degrading the appearance of the motorcycle.

This cooling effect is enjoyed even when the engine E is operated at low speeds or during idling. Also, because hot air is exhausted to the outside from the right radiator 23_(R), thermal damage to auxiliary apparati that are provided near the front engine bank 20_(F) of the engine E is effectively prevented.

This arrangement also has little or no effect on driveability of the motorcycle and actually increases rider comfort by more effectively cooling the motorcycle.

Because the radiators 23_(L) and 23_(R) are provided on both sides of the front engine bank 20_(F) of the water-cooled engine E and are inclined to provide a larger space between the top ends of these radiators 23_(L) and 23_(R) than the space between the bottom ends, the air-cooled oil cooler 30 can have a shape which extends relative to the width direction of the motorcycle. In this way, the oil cooler 30 can have increased surface area when compared with conventional oil coolers. Furthermore, this arrangement permits the oil cooler 30 to be efficiently cooled by cooling air generated by the cooling fan 24.

Still further, the inventive arrangement provides a relatively large empty space under the oil cooler 30 which permits increased air flow over the engine E and, thereby, more efficiently cools at least the front engine bank 20_(F) of the engine E.

Although this invention has been described in relation to a two cylinder engine, it is to be understood that the principles taught herein could be equally applied to four cylinder engine. Furthermore, the inventive arrangement could also be flipped such that the cooling fan is provided on the left side of the motorcycle.

The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims. 

We claim:
 1. A radiator configuration for a motorcycle having a V-type, water cooled engine, comprising:a first radiator mounted to a frame on a first side of the motorcycle, and a second radiator mounted to the frame on a second side of the motorcycle, an oil cooler provided in front of the engine and between said first and second radiators.
 2. The radiator configuration according to claim 1,said first and second radiators inclined relative to a center line of the motorcycle such that an inter-radiator spacing is larger at an upper portion of said radiators than at a lower portion of said radiators.
 3. The radiator configuration according to claim 2, said oil cooler laterally extending across a width of the motorcycle in the larger inter-radiator spacing provided between the upper portion of said first and second radiators.
 4. The radiator configuration according to claim 1, wherein forward portions of said first and second radiators project forwardly from a front end of the engine.
 5. The radiator configuration according to claim 1, the frame of the motorcycle including a pair of main frames and a pair of first and second auxiliary framessaid first radiator mounted to the first auxiliary frame, said second radiator mounted to the second auxiliary frame.
 6. The radiator configuration according to claim 5, further comprising:a support member connected to said first and second auxiliary frames, said oil cooler mounted to said support member.
 7. The radiator configuration according to claim 1, wherein the engine is offset relative to the center line of the motorcycle, said first and second radiators symmetrically mounted relative to the center line of the motorcycle.
 8. A cooling system for a motorcycle having a V-type, water cooled engine, comprising:a first radiator mounted to a frame on a first side of the motorcycle, a second radiator mounted to the frame on a second side of the motorcycle, and a coolant circulation system connected to said first and second radiators in parallel with the engine, an oil cooler provided in front of the engine and between said first and second radiators.
 9. The cooling system according to claim 8, said coolant circulation system including:a common guide tube connected to the engine and a rear of said first radiator, a first guide tube connected to the rear of said first radiator and to a front of said second radiator, a second guide tube connected to a front of said first radiator and to a rear of said second radiator, a return guide tube connected to the rear of said second radiator and to the engine, and a circulation pump connected to said return guide tube.
 10. The cooling system according to claim 8,said first and second radiators inclined relative to a center line of the motorcycle such that an inter-radiator spacing is larger at an upper portion of said radiators than at a lower portion of said radiators.
 11. The cooling system according to claim 10, said oil cooler laterally extending across a width of the motorcycle in the larger inter-radiator spacing provided between the upper portion of said first and second radiators.
 12. The cooling system according to claim 8, wherein forward portions of said first and second radiators project forwardly from a front end of the engine.
 13. The cooling system according to claim 8, the frame of the motorcycle including a pair of main frames and a pair of first and second auxiliary framessaid first radiator mounted to the first auxiliary frame, said second radiator mounted to the second auxiliary frame.
 14. The cooling system according to claim 13, further comprising:a support member connected to said first and second auxiliary frames, said oil cooler mounted to said support member.
 15. The cooling system according to claim 8, wherein the engine is offset relative to the center line of the motorcycle, said first and second radiators symmetrically mounted relative to the center line of the motorcycle. 